This is an interdisciplinary, site-specific modeling study focused on the Georges Bank conducted within the GLOBEC -Global Ocean Ecocsystems Dyanamics framework of the U.S. Global Change Research Program. It involves a collaborative effort on the part of U.S. and Canadian scientists at the Department of Fisheries and Oceans. Biological and physical data will be examined with the aid of three-dimensional circulation models under development at Dartmouth College and Skidaway Institute of Oceanography. The study will focus on sea scallops (Placopectin magellanicus), Atlantic cod (Gadus morhua) and the copepod Calanus finmarchicus. Larval drift models driven by the circulation models will be created and used to determine the extent to which egg and larval distributions on Georges Bank can be explained by the monthly-mean circulation fields; and to evaluate the significance of simple behaviors (vertical migration) and more complex physics (time-dependence, spatial structures) to the egg and larval distributions. The general approach will be to focus on the null hypothesis that distributions are determined by passive advection and diffusion in the monthly-mean circulation fields, and the corollary that apparent "retention" is merely a reflection of the Bank's natural residence time. Hypotheses for significant influences from higher-frequency flow variability, small-scale flow structures and vertical migration will also be explored.